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June 19, 1945- v. F. BAUMGARDNER MATER IAL SPREADER Filed July 28, 1942 3 Sheets-Sheet l I I I l -HMHJ I HT o June 1945- v. F. BAUMGARDNER MATERIAL SPREADER 3 Sheets-Sheet 2 34 Filed July 28, 1942 IFII June 19, 1945. v. F. BAUMGARDNER MATERIAL SPREADER 3 Sheets-Sheet 5 Filed July 28, 1942 Patented June 19, 1945 UNITED STATES :PATENT OFFICE Claims.

This invention comprises a novel construction of spreading machine for distributing aggregates for paving or surfacing of roads, landing fields, and the like, and a new method of performin the spreading operations incident to such paving or surfacing according to the amount and kind of work required to be performed by the machine.

This application is a continuation-in-part of my application Serial No. 447,562, filed June 18, 1942.

My machine is generally adapted to spread aggr gate material over a road subgrade, or the like, and may be used under some conditions Where the aggregates are not mixed with bonding agents, or under conditions where the aggregate is to be laid with bonding agents. The machine may be adapted to be attached to a suitable power driving or pulling unit including a tractor, in which case means for attaching the same to such unit will be provided. However, the embodiment of my invention to be hereinafter described is shown as being mounted at the rear f a self contained power machine in which aggregate may be mixed and supplied to the spreading mechanism. The spreading means utilizes in a general way the known construction of spiral spreading blades for distributing completely mixed aggregates on the subgrade, followed by a strike-off means for leveling the mixed aggregates to a predetermined grade line. However, the device is designed in an especially novel manner in that it is composed of spreading parts or members which are operable to rotate during the advancing movement of the machine, susceptible of being driven independently by virtue of the provision of certain differential drive mechanism that enables the separate sections or members of the spreader unit automatically to operate at different relative speeds, or one of them to cease operation while the other continues t spread, dependent on the conditions of the spreading work to be done, all as more fully set forth hereinafter.

The purpose of this construction is to deal with certain conditions of laying and spreading of pavement aggregates since at certain times more aggregate is required to be used to pave to even depth at one portion of the subgrade than is necessary at another portion. Unevenness or incorrect crown in the surface of the road subgrade, cavities, or the like, may give rise to the above condition. Therefore, relative rotation of the spreading members is desirable since more material may hav to be spread by one of them. In other words, each member may be called on to do more work than the other at different times. The differential drive mechanism for the members thus allows one to slow down or stop if necessary, while the other continues to rotate, or is accelerated in rotation, and vice versa, since the relative speeds or movements of the respective spreading members may be varied incident to the action of said gear mechanism.

A further object provides that when more material accumulates at one side of the spreader unit than is required to maintain the correct grade line, the spreading member on that side stops or slows down until the excessive pressure is released. Thus the crowdin of unneeded material to one side of the machine is eliminated.

The operation of the members of the spreader unit is thus facilitated even though the subgrade itself may not be perfectly level or may have holes or pocketsin certain places.

It is a further object of this invention to set forth a novel method of effecting the spreading of aggregates on a road subgrade, or the like, wherein the spreading action of the device to be described is automatically regulatable to correspond with the requirements of the subgrade being supplied with aggregate, whereby the continuous spreading action is facilitated, and an even road subgrade of desired crown is provided after the spreading action has taken place.

Further and more particular objects of this invention will be set forth in the specification appended hereto and claimed in the claims.

In the drawings:

Figur 1 is an elevational view of a machine howing the material spreading device supported thereby and illustrating certain of the instrumentalities availed of for effecting the spreading action.

Figure 2 is a sectional view taken about on the line 2-2 of Figure 1, illustrating the respective drive means for the spreader unit and certain instrumentalities availed of in conjunction therewith.

Figure 3 is a fragmentary view showing the drive means for the respective spreader unit and the machine on which the same is mounted, the same being broken away from th right hand side of Figure 2.

Figure 4 is a fragmentary view showing one end of a spreading member and the drive therefor, On line 4-4, Fig. 1.

Figure 5 is a fragmentar sectional view showing the differential drive mechanism, the same being generally of conventional form.

Figure 6 i a somewhat diagrammatic view of a road subgrade looking down thereupon, illustrating a depression therein.

Figure 7 is a sectional view taken about on the line II of Figure 6, illustrating aggregate in place on the road subgrade and in the depression thereof.

Figure 8 is a sectional view taken about on the line 88 of Figure 6.

Figure 9 is a sectional view bringing out more clearly the bearings for the spreader shaft and sprocket drive means for same including the supporting arm structure for said shafts.

In the drawings, Figure 1 shows the device attached to a mixing machine primarily for the purpose of illustrating one embodiment thereof, the mixing machine in this particular instance being not necessarily of any particular form but may be, as will appear hereinafter, of any construction whereby the device may be attached thereto, or the device may be supported by a l suitable traction means as a truck, or the like, for transportation over the road subg-rade.

The spreader unit of my invention comprises a pair of oppositely pitched spiral blade sections or spreading members I and 2. These spreading members are suitably fixed on sleeve shafts 3 and 4 disposed end for end, or in alignment, each sleeve of said sleeve shaft having the spiral blade thereof suitably formed therewith, and the spiral blades are pitched in opposite directions.

The sleeve shafts of the members I and 2 are carried by a supporting shaft 5, the ends of said sleeve shafts being supported in bearings at the rear lower extremities of the arms 6. The arms 6 are pivotally supported at their forward ends upon the opposite ends of the housing I of the differential drive mechanism located transversely of the device, and for the purposes of this disclosure supported near rear wheels 8 of the machine upon which the device is mounted, and carried by the frame 9 thereof.

The drive for the wheels 8 is effected from a motor 8a mounted on the frame 9, a drive shaft 8b transferring the power to the rear axle 80.

This differential drive mechanism includes the housing I, more particularly illustrated in Figure 5, and drive shaft members I and II mounted therein, the said members driven by suitable differential gearing I2 of conventional design in the gear box of the drive mechanism. The differential mechanism is driven by a drive shaft I3 which is provided with suitable universal joints I4. the said drive shaft I3 leading forward to a gear box I5, where it is connected by any suitable driving means tothe output shaft I6 of an automotive transmission connected to an engine I'I.

Reverting to the spreading members I and 2, the outer ends of the sleeve shafts of which are freely rotatable in the bearings I8, it is noted that at the outer end of each of the sleeve shafts of members I and 2 there is carried a sprocket gear I9 connected by sprocket chains to sprocket gears 2I, one of which is carried by each end of the respective differential drive shafts l0 and II. previously referred to.

The gears I9 and 2I and the sprocket chains 20 are housed in the hollow portions of the arms 6 so that the said driving means is protected and enclosed as will readily appear. Additional chain tensioning s rockets 27. and 23 are provided within the hollow portions of the arms 6, as will be noted upon consideration of Figure 1.

At the rear ends in which are located the driving sprockets IQ of the arms, the said arms are formed with upstanding portions 24 which are attached to a cross bar 25, which is substantially of the same length as the spreading members combined, and said cross bar has a center lift hanger 25 which is coupled by a pivot joint 21 to the lower end of a raising and lowering shaft 28 which extends at its upper end through a cross member 29 upon a frame unit 30 fastened in any suitable way to the rear end of the body of the vehicle by which the material spreading device is supported and transported.

The upper end of the raising and lowering shaft 23 is threaded, as will be apparent from consideration of Figure l, and a rotatable hand wheel 3| screws upon a threaded portion of said shaft 28 and has a bearing against the upper side of the cross piece 29 so that by turning the wheel 3! the operator, who may stand on the operator's station A, can readily elevate or lower the cross bar 25 and the arms 6 connected thereto.

The cross bar 25 has the center lift hanger member 26 by which it is connected to the spreader unit through the end arm extensions 24 to provide a properly rigid connecting and supporting means between the member 25 and the spreading members of the arms 6 of the spreading unit, which pivotally carry said spreader unit for raising and lowering adjustment thereof.

When the device is to be transported from one place to another, the spreader unit is disposed in a raised position by means of the raising and lowering means previously described. The spreading members, of course, may be lowered to the positions shown in Figure 1, when they are actively engaging the aggregate materials laid upon the subgrade and passing thereto from the mixer, or other source of aggregate supply, through any suitable means, as the chute 32, whereby the aggregates are deposited on the subgrade just in advance of the blade members I and 2 of the spreader unit.

In the rear of the spreading members I and 2. there is provided a strike-off plate 33, with certain combination skid and form member 34, one provided at each side of the machine. These skid and form members are availed of in the present embodiment of the invention to confine the aggregates deposited on the road subgrade in advance of the spreading members I and 2, and, therefore, may be provided with suitable means for raising and lowering the same in conjunction with the raising and lowering of the strike-oil plate 33, previously described, these raising and lowering means being of any conventional form and not forming a part of the invention set forth herein. The purpose of the skid, and form members in this particular instance is to confine the materials adjacent the ends of the screw members I and 2, as previously mentioned. The skid and form members are provided at their rear ends with upstanding arms 34a, and are connected by a rigid cross bar 35. These members may be of somewhat less length than herein disclosed, in so far as they perform the necessary function of confining the material substantially within the length of the spreadin members I and 2.

Projections or lugs 36 extend rearwardly from the cross bar 35 and overlie the strike-off blade 33. Adjusting shafts 31, turnable by hand wheels 38, are screw threaded into the lugs 36 for adjustable connection therewith, the lower ends of the shaft 31 being swivelly connected at the upper portions of the strike-off blade 83 at the ends thereof so that by rotation of the shafts 81 both ends of the strike-off plate 38 may b elevated orlowered.

When the shafts 31 are independently operated either end of the strike-off blade may be elevated relative to the other to meet the conditions of proper striking off of the pavin material to a proper crown of the road being laid. On the inner sides of the skid and form members 31, at their rear ends, are provided suitable guide means not shown, between which guide members not shown attached adjacent to the ends of the strikeoff blade 33 pass, so that the members 34 cooperate with the strike-off blade or unit for guiding the upward and downward movement of the latter in its adjusting action. I

With the foregoing construction of the spreading device in mind, the operation thereof is unique and highly efficient, and will now be described:

As previously stated, the drive for this unit comes from the engine I! by means of the shaft I3 rearwardly to the differential drive unit generally designated B in the drawings. The shaft l3 carries the power to the differential shaft me1nbers I and II from the gearing I?! in the housing 1, reference being made at this point to Figure 5. The shaft members I0 and II carry the drive through the sprocket chains 2!! in the housings of the arms 6, and thereby to the outer ends of the spreading members I and 2. In this manner, the members I and 2 revolve in one direction. As the aggregate materials are fed to the road subgrade in advance of the spreading members I and 2, they are deposited about centrally of the subgrade area and are engaged by the oppositely pitched blades so as to be spread transversely of the subgrade and evenly distributed ahead of the strike-off.

If the aggregates should pile up more on one of the spreading members I or 2 by reason of the fact that the subgrade is not adapted to receive a suflicient quantity of aggregate to permit the same to pass rearwardly of the strike-off, one of the members will slow down or stop, and the opposite member will continue rotation thereby distributing the material over the subgrade as required to maintain level of the roadway.

If the quantity of material pilin up at the slowed down or stopped member is sufiicient to permit a gravitational flow to the other member, this will take place, and all additional material will flow to the other side until sufficient has passed under the strike-off to reduce the pressure on the stopped or slowed down member, whereby the same may subsequently begin rotation because of the difierential action of the differential drive unit B in respect to the spreading members I and 2.

Reference at this point is made to Figures 6, 7 and 8, the same being diagrammatic illustrations of a road subgrade illustrative of a condition that may arise whereby the differential action of tho spreader unit is availed of to properly level the aggregates over the subgrade, Figure 6 illustrating generally a depression or other unevenness in the surface of the subgrade as at 39. If we assume that the ma chine is passing in the direction of the arrow shown in Figure 6, it will be apparent that when aggregates deposited on the subgrade in advance of the spreading members I and 2 are deposited just over the depression 39. addi tlonal material will be required to fill this depression to thereby even the same and form a level properly crowned road grade. Therefore, the

spreading member, the same being the left hand member 2, will speed up in order to deposit sufficient material in the depression.

This will be apparent since there is less resistance on that spreading member and thereby more material will be deposited in the depression. The spreading member I, being the right hand member, does not require as much material since that portion of the subgrade is relatively level and will thus be moving slower relatively to the spreading member 2, just referred to.

When the machine has passed sufliciently far enough along the subgrade whereby the end of the depression is reached, the resistance offered by the material on the spreading member 2 will increase since the amount of aggregate required to be deposited is lessened, and thereby that member will slow down to substantially the same rate of speed as the member I, and thus the spreading operation will be effected in a normal manner again.

It will be apparent that under some conditions, more or less material is required to be deposited in various places over the subgrade surface, and, as above set forth the differential action of the spreader unit will automatically compensate for the requirements of the grade level of the road, and the aggregates will be spread evenly thereover to be subsequently properly leveled by the strike-off blade or plate.

From the foregoing, it appears that the resistance of the material is the factor which affects the rotational action of the respective spreading members I and 2, the same being varied automatically in accordance with the requirements as above set forth.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a material spreading device of the class described, means for supporting said device for travel movement over a subgrade, a spreader unit including independently driven spreading members, and means for automatically varying the driving speeds of said members incident to variation in resistance offered to the spreading members as they act on the material being spread.

2. In a material spreading device of the class described, means for supporting said device for travel movement over a subgrade, a spreader unit including independently driven spreading members having spreading means which operate in opposite directions, and driving means for said members responsive to the resistance afforded by the quantity of material engaged by and to be spread by said members, to independently regulate the relative spreading movements thereof.

3. In a material spreading device of the class described, means for supporting said device for travel movement over a subgrade, a spreader unit including independently driven spreading members having spreading means which operate in opposite directions, and means for driving said members responsive to variation in the resistance to movement of said members during the spreading operation, including means for automatically varying the relative speeds of said members as determined by resistance of the mass of material to be spread, engaged by the members.

4. A material spreading device of the class described, in combination, a spreader unit including separate spreading members independently rotatable on said unit, power means for said unit, instrumentalities adjacent said members for transversely confining material to be spread, differential gear mechanism connecting and for driving said members at difierent speeds, and means for supporting said device for travel movement.

5. A material spreading device of the class described, in combination, a spreader unit, including independent spreading members rotatably mounted on said unit, power means for said unit, instrumentalities adjacent said members for confining material to be spread, differential gear connected shafts connected to the spreader members and operated by the power means and responsive to the resistance of the mass of material confined by said instrumentalities for driving said members, means for supporting said device for travel movement, and strike-off means rearwardly of said spreading members.

6. A material spreading device of the class described, in combination, separate transverse spreadin members, means for transversely confining material to be spread in advance of said members, common drive means for said members, includin instrumentalities responsive to the resistance of a mass of material operated on by the spreading members, for moving said members at the same or different spreading speeds.

7. A device as claimed in claim 6, wherein the spreading members comprise oppositely pitched spiral screws.

8. A machine as claimed in claim 6, wherein the Spreading members comprise oppositely pitched spiral screws, supported on a common axis and the drive means include a differential axle unit and power transmitting means at opposite ends of the axle unit connected with the spreading members.

9. A device as claimed in claim 2, wherein the spreader unit is disposed transversely of the supporting means and the spreading members comprise oppositely pitched spiral screws having a common axis, and spaced supporting arms engaging the screws, the resistance responsive means include a housing carried by the supporting means, differential gearing, and shafts driven thereby in said housing, the shafts being drivably connected with the ends of the screws, and the spaced arms pivotally engaged with the ends of the housing aforesaid.

10. In a material spreading device of the class described, means for supporting said device for travel movement over a subgrade, a spreader unit including independently driven spreading members, and means for automatically efiecting stoppage of one spreading member whilst the other is being driven controlled by variation in the resistance ofiered to the movement of the spreading members by the material engaged and being spread thereby.

VERSAL FORREST BAUMGARDNER. 

